U.S. patent number 5,095,302 [Application Number 07/368,485] was granted by the patent office on 1992-03-10 for three dimensional mouse via finger ring or cavity.
This patent grant is currently assigned to International Business Machines Corporation. Invention is credited to James G. McLean, Clifford A. Pickover, Alvin R. Reed.
United States Patent |
5,095,302 |
McLean , et al. |
March 10, 1992 |
Three dimensional mouse via finger ring or cavity
Abstract
A cursor control/data input device for a computer display system
which utilizes a conventional X-Y mouse provided with a third Z
with axis data generating mechanism. The mouse may be used with any
non-specific support surface and would have conventional X-Y data
generating wheels or a rotating ball with appropriate pick-up
elements to generate the X-Y coordinate data. Third, or Z,
coordinate data is produced by a third instrumentality in the mouse
body, preferably operable by the operator's thumb or index finger.
Means comprising a pressure sensitive button mounted on the surface
of the mouse, or alternatively means actuated by the insertion of
the operator's finger into a hole provided in the mouse's body,
generate said Z coordinate data. Movement of the finger in the hole
is measurable by any of a number of different
instrumentalities.
Inventors: |
McLean; James G. (Boyton Beach,
FL), Pickover; Clifford A. (Yorktown Heights, NY), Reed;
Alvin R. (Cary, NC) |
Assignee: |
International Business Machines
Corporation (Armonk, NY)
|
Family
ID: |
23451420 |
Appl.
No.: |
07/368,485 |
Filed: |
June 19, 1989 |
Current U.S.
Class: |
345/164;
345/165 |
Current CPC
Class: |
G06F
3/03543 (20130101); G06F 3/033 (20130101) |
Current International
Class: |
G06F
3/033 (20060101); G09G 003/02 () |
Field of
Search: |
;340/706,709,710,712
;200/52R,329,5R ;341/20,23 ;364/200,900,190 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
0000828 |
|
Jan 1986 |
|
JP |
|
0004166 |
|
Jul 1986 |
|
WO |
|
Other References
Fox, "Keyboard Scanned Capacitive Joy Stick Cursor Control", IBM
Technical Disclosure, vol. 23, No. 8, Jan. 1981, pp. 3831-3834.
.
Cummings, "Transparent Keyless Keyboard for Variable Terminal
Applications", IBM Technical Disclosure, vol. 20, No. 4, Sep. 1977,
pp. 1609-1611..
|
Primary Examiner: Ng; Jin F.
Assistant Examiner: Popovici; Dov
Attorney, Agent or Firm: Schlemmer; Roy R.
Claims
We claim:
1. In a cursor control/data input mouse including a mouse body and
first and second X-Y movement pick-up means providing data signals
indicative of the relative movement of the mouse across a planar
surface in the X and Y directions, the improvement which
comprises:
third means in said mouse body responsive to generate a signal
representing a third input parameter by the user comprising a hole
for receiving a user's finger and signal generating transducer
means in said mouse body mounted in cooperative relationship with
said hole responsive to measure the depth of penetration of a
user's finger axially within said hole, wherein said finger is not
necessary for movement of the mouse, and said third parameter is
capable of representing a movement along a z dimension.
2. A cursor control/data input mouse as set forth in claim 1,
wherein said signal generating transducer means comprises a
pressure sensitive transducer located within said hole and
resilient means operable in cooperation with a user's finger for
proportionally increasing the pressure on the transducer as the
user's finger is inserted further into said hole.
3. A cursor control/data input mouse as set forth in claim 1,
wherein said signal generating transducer means comprises a series
of light source/photo detector pairs located on opposite sides of
said hole throughout the length thereof, and control means
operative in conjunction therewith to measure the depth of
penetration of a user's finger as a function of the number of photo
detectors deactivated as the finger is inserted.
4. In a cursor control/data input mouse including a mouse body and
first and second X-Y movement pick-up means providing data signals
indicative of the relative movement of the mouse across a planar
surface in the X and Y directions, the improvement which
comprises,
third means in said mouse body responsive to generate a signal
representing a third input parameter by the user, responsive to the
substantially axial movement of one finger of a user, said finger
not being necessary for the movement of the mouse, said third
parameter being capable of representing a Z dimension,
said third means comprising a hole in said mouse body for receiving
a user's finger and signal generating transducer means in said
mouse body mounted in cooperative relationship with said hole for
measuring the depth of penetration of a user's finger axially
within said hole,
said signal generating transducer means comprising a surface
acoustic wave (SAW) device located at the bottom of said hole and
resilient means associated therewith mounted so that as a user's
finger presses on said resilient means the area of contact between
said resilient member and said SAW device increases thereby
changing an output signal produced by said SAW device.
Description
FIELD OF THE INVENTION
The present invention relates to the field of electro-mechanical
data input devices for communicating with video display systems and
the like, and particularly to such data input devices where the
control of a cursor and/or pointer on the screen of the display is
able to respond to three input dimensions.
BACKGROUND OF THE INVENTION
Data input or communication from a user to a computer is possible
using many different known input devices. The most common is a
typewriter-type keyboard which is coupled directly into the
computer system. As will be well understood, computer systems
conventionally include a display device of some sort normally of
the CRT monitor type which is capable of displaying on the screen
any information, be it graphical or text, being currently examined
or input by an operator. The monitor is also the usual vehicle
allowing a visual display of the communication between the operator
and the system. A display is also frequently used to generate
graphics together with suitable data input devices and the display
is the usual mechanism by which the operator is able to relate
interactively with the computer by suitably manipulating data or
graphic images on the screen. The usual way in which the
user/operator actively interacts with the computer is to move a
cursor or pointer selectively on the display screen where the
movement may either comprise raw data input or may indicate certain
sections of the display which has significance to the task being
performed by the operator.
Many types of devices have been developed and are currently known
in the industry which allow a user/operator to selectively move the
cursor spot on the display screen. These include cursor keys on the
keyboard which move the display cursor orthogonally, i.e., along X
or Y axis, light pens, joy sticks, and various types of mouses
whose X--Y axis motion may be detected and conveyed to the system
where the X--Y motion data is converted into cursor movement. Thus,
the movements of the user/operator's hand are translated by the
input devices into positional coordinate information or commands
which the computer is able to interpret and utilize same to move
the cursor appropriately.
For most applications, moving the cursor conventionally in the X-Y
direction is adequate since the screen is two-dimensional and many
applications require only two dimensions. However, for certain
applications it is desirable to have a third input dimension or Z
axis movement which can, with appropriate software support, very
conveniently allow the operator to, for example: pick a particular
location within a three dimensional isometric graphical display or
select a particular menu in a three dimensional menu display as is
well known in the art.
Other major applications might be to control an image "zoom"
function (to magnify or de-magnify an object) or to translate an
object.
The device is not limited to 3D selection or picking. It can be
also used to translate or magnify an object or image. For example,
the user may display a 3D molecular graphic, or an image of the
ground from an airplane. The new control mechanism can allow the
user to magnify the molecular model or the image. Alternatively,
the third dimensional control can be used to translate a model in a
direction orthogonal to the standard 2D screen directions.
It would also be possible for the 3rd dimensional input means to
control other graphic features, such as color, intensity, etc.
There are no known mouse designs currently on the commercial market
allowing for the inputting of third i.e. Z, dimension data via a
mouse type of cursor control device. It's obviously to the
advantage of the mouse design that the particular mechanism for
introducing the Z dimension be natural i.e., be intuitive and be
easily implementable electronically to introduce said third
dimension into the display system. It is believed that the present
three-dimensional mouse satisfies these requirements.
Prior Art
U.S. Pat. No. 4,736,191 of Matzke et al., entitled: "Touch
Activated Control Method and Apparatus" discloses a very complex
cursor control device comprising a touch-pad formed of a plurality
of individual conductive plates formed in a predetermined
arrangement. A user's touch is detected via a change of capacitance
in certain areas of the plate resulting from the user's finger or
hand on the pad. A relatively complex circuit arrangement is
required for detecting which portion of the pad has been touched by
the user and X-Y coordinates are determined primarily as a function
of the portion of the pad touch and the Z coordinate is developed
as a function of the total area touched.
The present invention relates to a conventional X-Y mouse
input/cursor control device augmented by the addition of a third
sensing element built into the mouse body which basically senses
movement or pressure applied by the thumb or index fingers. It may
also be utilized with existing (X-Y) display system architecture
with minimum modification.
In an article entitled: "Keyboard Scanned Capacitive Joystick
Cursor Control" by J. E. Fox appearing in the IBM Technical
Disclosure Bulletin Volume 23, Number 8, January 1981, pages 3831
thru 3834 discloses a joystick cursor controller which, similar to
the Matzke et al. patent, utilizes a change of capacitance which is
picked-up by the sensing circuitry that translates into X-Y
movement of the cursor. Although, a measurement of change of
capacitance is one way in which the present three-dimensional mouse
could generate the Z coordinate data, the particular way in which
capacitance is measured in the above article has little resemblance
to the structure or function of the subject invention.
The art is, of course, replete with various types of X-Y mouse
input mechanism, however, none is known to the inventors which
provide for the inputting of Z coordinate data.
SUMMARY AND OBJECTS
It is a primary object of the present invention to provide a
three-dimensional mouse input/cursor control device capable of
generating data in the X, Y and Z dimensions.
It is a further object of the invention to provide such a mouse
which is both convenient and intuitive for the operator to provide
the Z dimension data.
It is another object to provide such a mouse wherein the Z
dimension input is a function of pressure or movement of the thumb
or one of the fingers of the operator on the mouse's body.
It is yet another object to provide such a mouse wherein the means
for generating Z input data comprises an opening in the mouse's
body into which an operator's finger may be inserted, the magnitude
of the signal being proportional to the degree of insertion.
The objects of the present invention are accomplished in general by
a mouse cursor control input system for a computer display system
or the like having conventional X, Y motion pick up means mounted
in the mouse's body. The improvement of the present invention
comprises providing a third or Z dimension input signal generating
means in the mouse's body which is easily activated by pressure on
or movement relative to the mouse's body by the thumb or one of the
fingers of the operator.
In the preferred embodiment of the invention a hole or finger
cavity is provided in the mouse's body into which a finger may be
readily inserted, and the depth of penetration detected by suitable
means as an indication of the Z dimension signal magnitude.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 comprises a cross-sectional isometric view of a preferred
embodiment of a three-dimensional mouse constructed in accordance
with the teachings of the present invention.
FIG. 2 comprises graphical representation of a three-dimensional
body upon a display screen illustrating the use of the X, Y and Z
coordinates to locate a cursor in all three dimensions.
FIG. 3 comprises a high level functional block diagram illustrating
how the X, Y and Z inputs generated by movement of the mouse are
transmitted to the inputs of a personal computer for controlling a
cursor movement on the display screen.
FIG. 4 comprises a series of light source/photo detector pairs
located on opposite sides throughout the length of the hole.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Display system input mice have proven to be effective and intuitive
pointing devices for applications requiring one dimensional
movement up and down thru a menu list or for two dimensional
movement around the screen under a "paint" program's control.
However, movement control in three dimensions has heretofore been
limited to complex and non-intuitive approaches as in the Matzke et
al. patent referenced previously. The present invention extends the
intuitive mouse approach into the third dimension.
In the following description of the invention several embodiments
of a three dimensional mouse will be set forth and discussed. All
of the embodiments are simple and yet effective in providing a
third input dimension which is both physically easy to use and
intuitive on the part of the user.
The first involves using a piezoelectric pressure transducer (PPT)
which is added to an otherwise conventional mouse design to provide
the capability for natural and intuitive pointing in three
dimensions.
In the second, an elongated ring is added to the mouse's body into
which a finger is inserted. The ring may resemble a standard
finger-ring worn on a person's hand. However, for the present
invention, the ring is attached to a vertical post which is adapted
to move axially into or out of the mouse. In other words, the ring
may protrude above the mouse by half a centimeter. Movement of the
ring up or down may be detected.
The ring would be attached to a string which is wound around the
shaft of a potentiometer. Raising the ring causes the potentiometer
to turn, varying the resistance of the pot. This change in
resistance would be detected by the mouse circuitry. The pot shaft
is spring loaded to automatically return to a default position.
Thus, movement of the ring can be used to indicate a third
dimension for graphics purposes. This is better than a simple
pressure pad, because up and down movements are easily and
intuitively mapped to a coordinate which is, of course, a more
natural motion for the user or operator than merely maintaining
pressure.
In yet, another embodiment a hole is placed in the middle of the
mouse's body into which one inserts e.g., the index finger. The
depth of penetration may be measured by a number of different
means. Optical means could be employed wherein a plurality of a
light emitting diodes (LED) and associated photo-detectors, e.g.,
photo-conductors (PC) located on opposite sides of the hole would
be capable of measuring said depth of penetration.
A further means for measuring depth of penetration could utilize a
piezoelectric pressure transducer (PPT) at the bottom of the hole
which will be described subsequently.
In the previously described PPT embodiment the PPT is utilized to
measure pressure of the mouse body into the support surface. As is
well known, a PPT is a solid state device for converting pressure
applied thereto into a corresponding electrical voltage more or
less proportional to the amount of pressure applied. PPT's are
found most often in transistorized scales and other measuring
equipment, and are capable of very sensitive pressure detection. In
this embodiment the PPT would be placed in the lower portion of an
otherwise conventional optical or rolling-ball mouse, separated
from the ball by a compressed felt pad. The X-Y axes of movement
are controlled in the normal mouse manner. "Pointing" in the Z axis
is accomplished by applying pressure to the mouse more or less
perpendicular to the surface on which the mouse is moving which
translates into pressure on the PPT.
Circuitry within the mouse converts the voltage received from the
PPT to signals indicating Z dimension data which are relayed to the
display system along with the other mouse movement signals
representing motion in the X-Y dimensions.
The PPT circuit combination is calibrated so that excessive
pressure, which might prevent easy X-Y movements is not required,
but that normal hand pressure does not cause signals representing Z
movements to be generated. Thus, a simple upper and lower treshold
would be provided.
The concept of moving a cursor or other pointer on the screen in
the X-Y dimension while "pushing" it into the Z dimension is
intuitively comfortable. Intuitive, as used herein, refers to the
natural mental-physical reaction of the user to perceive the need
for and achieve such Z access movement easily and automatically.
Normally, it is difficult for a person to even think in the Z
dimension, much less perform a third-dimensional hand movement,
especially, while working on a two dimensional surface. It is,
further, necessary that this Z directional movement be carefully
controlled to appropriately move the cursor, as will be well
understood. With all of the disclosed embodiments of the present
invention, this same intuitive feel is maintained.
In certain situations, pushing down on the entire mouse could
affect control over the normal X-Y movements of the mouse. For
these situations it is proposed that an alternate implementation be
utilized in which the PPT is included in the form of a non-moving
"button" on the side of the mouse (instead of being mounted on the
bottom of the mouse for contact with the surface). In this case the
thumb is used to press the button with varying degree of force as
the mouse is moved across a support surface in the normal manner.
In this implementation finer control of the cursor movement would
be possible, at the expense, however, of being slightly less
intuitive.
A preferred embodiment of the present invention utilizes a hole in
the middle of the mouse's body into which one may insert for
example: the index finger. The depth of penetration of the finger
may be measured as described above, by LED/PC sensor pairs located
along the hole on opposite sides thereof or some sort of capacitive
or acoustic sensing method could be utilized. This embodiment is
believed to be a preferred one because it is easier to maintain a
steady finger depth of penetration in the hole (a constant Z
dimension signal) while moving concurrently into the X-Y dimension
than with the two previously described pressure button
embodiments.
An advantage of the presently disclosed three-dimensional mouse is
its compatibility with all existing software products requiring
mouse X-Y signals. In this situation the Z axis or dimension
signals would simply be ignored for those applications needing only
the traditional X-Y mouse control of the cursor.
Examples of the types of existing software application where the
three-dimensional mouse might be useful are as follows. In
three-dimensional drawing programs such as CADAM systems such a
mouse may be used to design three-dimensional objects, usually the
designer is restricted to one two-dimensional view at a time. The
three-dimensional mouse allows access to all three dimensions at
all times.
A second use might be in a layered menu system. In this case the
mouse cursor moves "into" a screen of menu category "tiles". The
cursor is placed above one of these tiles at a pre-determined
position and "pushed down" or moved "inward" through a selection of
options under that category. When the desired tile is reached, an
appropriate button on the mouse is pressed to indicate that the
current option is being selected. Unlike hierarchical menu systems,
all categories are visible and all selections are available from
the same screen.
A further use would be for multiple parameter control other than
X-Y-Z spatial dimensions. Adding another dimension of control will
always be useful in situations when the computer provides a
real-time control signals, such as "waldo" control, full sound
parameter control of an electronic musical system, or control of a
lighting system or the like.
Waldo as used herein is a generic term for a remote-controlled
mechanical unit which mimics a human capacity. For instance,
waldoes in the form of mechanical arms and hands might be used
inside a nuclear reactor unit and could be controlled by the 3-D
mouse of the present invention providing data input to computer
controlled manipulating circuitry.
It is believed that many other uses for a third dimension with such
a mouse control system are possible. If such a device becomes
commercially available, it is believed that developers of current
mouse-friendly software systems would come up with innumerable
additional uses for such systems.
The preferred embodiment of the invention will now be set forth and
described with reference to the figures. In FIG. 1 a
three-dimensional control mouse constructed in accordance with the
teachings of the present invention is shown in perspective along a
cross-sectional plane taken through the middle of the mouse's body.
The left half of the mouse has been removed for visualization. This
unit allows the user to input three distinct analog signals to a
utilization display system or the like. Two of the analog signals
are the typical X and Y values or dimensions of the mouse movement.
The third analog signal is the Z dimension and is applied by the
method and instrumentality described subsequently.
The figure is functional in nature and only shows details
particularly relating to the present invention. Thus, the main body
(1) of the mouse contains all of the necessary means for generating
and picking-up X and Y signals as a well as the specifically shown
instrumentality for generating the Z signal. The body also provides
an attachment for the cabling (10) which provides power leads as
well as signal leads back to the host system as will be well
understood. In use, the user would rest his palm on the front
radius (2) of the mouse's body to control the movement of the mouse
as in any conventional X-Y mouse. The roller ball (3) is spherical
and produces the X and Y analog signals by suitable means well
known in the art. One or more standard control buttons (4) are
provided for controlling certain mouse functions as will also be
well understood.
According to the teachings of the present invention, a finger
cavity or hole (5) is provided to produce and control the Z analog
signal. The user places his finger in the cavity against the finger
button (6). When the user presses on the finger button the spring
(7) is compressed.
The compression of the spring is used to control the analog
measuring device. This spring presses a rubber ball (8) against a
surface acoustic wave (SAW) device (9) which is capable of
providing a reliable variable input. In such a device surface
acoustic waves with frequencies in the range of 7-10 Hz propagate
nondispersively along and are bound to solid surfaces. When the
rubber ball presses against the surface, it attenuates the wave
burst propagating across the surface. The SAW device generates an
output signal whose magnitude is dependant upon and proportional to
the amount of area the rubber ball covers. This is controlled in
turn by the amount of pressure from the user's finger. The degree
of deformation of the ball provides a uniform, accurate measure of
pressure and changes in pressure to, in turn, produce an analog
signal approximately proportional to the pressure applied. The SAW
technique allows an accurate analog output in a small, inexpensive
device. It is important that it does not require a large range of
motion for actuation over its entire output range.
As will be apparent, other obvious means may be utilized for
measuring the depth of penetration or motion of the finger into the
cavity such as the previously mentioned optical means wherein, for
example, a series of optical emitter/detector pairs could be placed
on opposite sides of the hole and, depending upon how many light
beams were interrupted, an accurate measurement of the range of
motion of the finger is readily possible.
Another way of measuring depth of penetration comprises using an
electromagnetic coil imbedded around the cavity in the mouse to use
with a metallic finger ring. The movement of the metallic finger
ring through the coil would give the Z output. This output would be
analog for a continuous coil or binary, similar to the X and Y
output, if stacked coils are used.
As will be apparent to those skilled in the art, still other means
can readily be used to produce an analog signal based on the
position of the finger button. The contribution of the present
invention involves the recognition of the importance of a third or
Z dimension input signal and the provision of means on the mouse's
body to produce such a signal, said means being intuitive on the
part of the user.
The three-dimensional mouse of the present invention thus has as
its primary advantage the availability of an additional analog
control input to the application software which it provides when
utilized in conjunction therewith. The user does not need to
control a separate device to achieve this third control
parameter.
FIG. 2 illustrates a three-dimensional object being drawn on a
computer screen. The X, Y and Z coordinate of each intersection
point on the object is being dynamically determined by the
three-dimensional mouse.
The current position (10) of the cursor denoted by the large cross
(+) symbol, is defined by an X offset (12) along the X axis, a Y
offset (14) along the Y axis and a Z offset (16) along the Z axis.
The X and Y offsets are produced by the standard rolling ball
located on the bottom of the mouse. The Z offset capability is
produced by utilizing one of the Z dimension input means included
in the mouse's body in accordance with the teaching of the present
invention such for example as the hole and pressure transducer in
the embodiment illustrated in FIG. 1.
The functional block diagram of FIG. 3 is illustrative of typical
instrumentalities within or associated with the mouse body which
produce the three-dimensional X, Y and Z inputs, converts them to
appropriate electrical signals which are then fed to a utilization
display system such as a personal computer. In the figure the
dotted line designated (1) comprises functional units which could
readily be included in the mouse's body. In this figure it is
assumed that the X and Y inputs as well as the signal generating
circuitry is conventional in nature.
The three blocks 31 marked X, Y and Z mouse input are
representative of the motion of the mouse, caused by movement
thereof by a user, which motion has been appropriately broken into
X, Y and Z dimension signals. The X and Y dimension input signals
would be derived as the motion of X and Y motion pick-up wheels
attached to the spherical ball in the embodiment of FIG. 1 and the
Z signal would be derived from one of the pick-up means described
previously.
Each of the X and Y physical inputs to the mouse introduces an
analog rotary motion in a movable sphere having both X and Y motion
take-off wheels such as are known in the art. These wheels produce
the X and Y analog output wave forms or signals 30 and 32. This
rotary motion may be utilized to turn a notched emitter wheel which
switches a light emitting diode/phototransistor (LED/PTX) on and
off in a proportional binary manner. The output signals 36 and 38
from the LED/PTX blocks 34 are illustrated as a variable square
wave which is in turn connected to X and Y positions on the input
bus to the personal computer 40. As will be well understood by
those skilled in the art, analog to digital conversion means can
also be included in the blocks 34 to produce binary signals
representative of the analog waves 30 and 32. These signals
comprise a sequence of binary values representing the repetitive
sampling of the analog signal as will also be well understood by
those skilled in the art.
The third mouse input referred to herein as the Z axis input is
provided by means of one of the instrumentalities set forth
previously e.g., 1) a pressure sensitive device in conjunction with
the main movement ball which measures pressure by the mouse on the
surface, 2) the hole or cavity utilizing either an optical pick-up,
a pressure sensitive pick-up or variable capacitance means, or 3) a
pressure transducer on the side of the mouse engageable by the
thumb. The specific manner of producing the Z signal is not
important to this description. The electronic analog signal from
the pick-up means (the Z mouse input on the figure shown as analog
wave 42) is fed to the analog to digital converter 44. The analog
to digital converter converts this signal as described above into a
sequence or continuous sampling of the analog wave which is
converted into 8 bit binary code which may be transmitted over the
bus 46 to the utilization means 40. As will be well understood, the
on-off state of the various lines of the bus define the sequential
8 bit values between 0 and 255 which is represented by the
continuous analog of the Z mouse input coming from the mouse. It
will, of course, be understood that the lines connecting the two
blocks 34 to a utilization device 40 could also be 8 line cables
similar to 46 if it were desired to replace the two blocks 34 with
analog to digital converters such as block 44 utilized to process
the Z mouse input.
Conclusions
A novel three-dimensional mouse structure has been described
incorporating the principals of the present invention which not
only provides for a third dimension or third input parameter, but
also and more importantly, allows this input to be intuitive on the
part of the user. It is believed that this inherent intuitive
characteristic of the mouse will greatly enhance its utilization in
future commercial products since a third or Z dimension criteria
has significant value. The mouse is usable in unaltered form on
standard two-dimensional input applications and can be, of course,
utilized for special applications written to utilize said third Z
dimension.
The design is simple and straightforward and can utilize any of a
number of existing technologies to easily and inexpensively achieve
the third-dimension input. Suitable application programs utilizing
the third-dimension may be easily written to provide, even greater,
user "friendliness" for the already widely accepted mouse input
technology.
While certain preferred embodiments of the invention have been set
forth and described, it will be appreciated that other obvious
modifications to the mouse may be made by those skilled in the art
to provide a third input dimension without departing from the
spirit and scope of the invention as set forth in the claims.
* * * * *